strange pressure pain in both knees

[simong]

I am 55 years old, 6 foot 6 inches, 230 lbs, I used to ride 20 miles a day on my bike for the last 20 years, since the last 2 years I have some kind of heavy pressure pain right above my knee caps, only while standing up, or taking the stairs 2 steps at a time, bending my knees while standing, is possible for the first part of the movement, 45 degrees is impossible because of the pain. (when I stand up from a chair, I use my hands to get up). Riding my bike gives less trouble because the pressure is much lighter.
Strangely enough, working on a Leg extension machine gives almost no pain, as long as I don't use heavy weights, more than 100 lbs.
For the rest there is no pain or swelling, with one exeption: although both knees are affected, my right knee starts to ache while driving my car for 20 minutes. (Knee bend). The solution is to stop and stretch my leg and the pain disappears instantly.

I would like to know what it is what I have, and what I can do about it.

Thanks,
Simon

[Heidi]

Hi
It sounds like a case of anterior knee pain (or patellofemoral knee pain - same thing): http://www.sportsinjuryclinic.net/cybertherapist/front/knee/patellofemoral_pain_syndrome.php
The solution to this is correcting muscle imbalances. The most common ones are tight lateral thigh muscles, ITB and groin and weak medial thigh muscles and glutes.
Work on correcting these and in the meantime a support with a buttress or a taping technique as shown on the section above may help.

[simong]

Thank you for your answer, Heidi.
All my life it was very difficult for me to sit on the ground with my legs crossed, it gave pressure on the outside of the knees. Recently I started to practice it to be able to do some Yoga.
As I read your solution this could be a good start ?
Simon.

[Heidi]

Yes definately give it a go!